A diminished (Adim) chord on piano

Looking for the Adim chord on piano? It is a diminished triad (two minor thirds), made of three notes: A – C – E♭.

Root position: A3 – C4 – E♭4

What the Adim chord sounds like

A diminished triad is two stacked minor thirds with a diminished fifth. It sounds tense and unsettled; in a major key it sits on degree vii and leads into the tonic.

Notes of the Adim chord

Degree	Note	Interval from the root
1	A	root
3	C	minor third (3 semitones)
5	E♭	diminished fifth (6 semitones)

Root position and inversions

An inversion uses the same notes, with a different note at the bottom. When you change chords, choosing the nearest inversion keeps your hand almost still.

Root position

A3 – C4 – E♭4

1st inversion

C4 – E♭4 – A4

2nd inversion

E♭4 – A4 – C5

Which keys is it in?

The Adim chord is built from the notes of these keys (for minor keys, both the natural and the harmonic minor are considered):

B♭ major: vii°
B♭ minor: vii°
G minor: ii°

Similar chords and substitutes

If Adim is too hard, or you want a different colour in the same spot, these chords are worth a try.

Substitutes (by function)

F7 – an incomplete dominant: the diminished chord is the top of this seventh chord
B♭ – where it leads (leading tone → root)

Richer versions

Adim7 – the same chord plus 1 colour note
Am7b5 – the same chord plus 1 colour note

Frequently asked questions

What notes are in the Adim chord?

A, C, E♭. The root is A; the intervals of the other notes from the root: minor third, diminished fifth.

How do I play the Adim chord on piano?

In root position, the right hand usually plays with fingers 1, 3 and 5 (thumb, middle finger, little finger); four-note chords with fingers 1, 2, 3 and 5. The left hand mirrors this: 5, 3, 1. In an inversion the top or bottom note moves to the other side, so your hand moves less when you change chords.

How is the Adim chord written?

The chord symbol is Adim, and its full name is A diminished.